The present invention generally relates to apparatus for controlling rotation of an output, with the output being selectively driven by an input or rotationally independent from the input and possibly rotatably related to a third member.
Clutches, clutch/brakes and other rotational control apparatus of various types and configurations are known in the art. Such apparatus typically allow free rotation in an unactuated position and can be pneumatically actuated. One type of such apparatus includes multi-plate friction interfaces due to their relatively small radial size and due to their relatively high torque.
However, there is always a need for improved rotational control apparatus which reduces complexity and/or which increases performance. It is desired that such improved rotational control apparatus be cost competitive with existing apparatus and/or may be aimed to somewhat specific applications such as in the preferred form to the conveyor clutch market.
The present invention solves this need and other problems in the field of rotation control by providing, in the preferred form, an automotive clutch release type bearing between the piston and the interface element so that axial force can be applied directly through the bearing without the use of a thrust plate or thrust bearing, with the bearing being capable of being unloaded as well as being self-contained to simplify the design of the rotational control apparatus.
In a preferred aspect of the present invention, the piston and the bearing between the piston and the interface element are encapsulated in the interface and/or piston cavity to inhibit exposure of the bearing to friction dust, dirt or other environmental contaminants which could inhibit bearing performance.
In still further aspects of the present invention, the interface element in a nonactuated position engages the axial end of the air chamber to eliminate rotational speed differences therebetween such as for holding the output stationary when the air chamber is rotationally stationary.
In further aspects of the present invention, the friction plate axially slideable relative to but rotatable with the input creates turbulent air to increase air flow allowing for higher thermal dissipation. In preferred forms, the outer circumferential edge is not circular and includes lobes and depressions such as in the form of a sine wave. Additionally, a plurality of passages are formed in portions which interface with an interface element, with the plurality of passages being equally circumferentially spaced and of noncircular shapes in the most preferred form. The interface elements with which the friction plate interfaces include a circumferential edge located intermediate the maximum and minimum radial extents of the plurality of passages.
In other aspects of the present invention, the air chamber and the mount preferably forming the output of the rotational control apparatus have the same geometry allowing machining from identical castings. Thus, identical bearings can be utilized, the design can be simplified, and the capital and production costs can be minimized.
It is thus an object of the present invention to provide a novel apparatus for controlling rotation.
It is further an object of the present invention to provide such a novel rotational control apparatus of a simplified design reducing complexity.
It is further an object of the present invention to provide such a novel rotational control apparatus having increased performance.
It is further an object of the present invention to provide such a novel rotational control apparatus which is cost competitive.
It is further an object of the present invention to provide such a novel rotational control apparatus providing increased air flow to enhance thermal capacity.
It is further an object of the present invention to provide such a novel rotational control apparatus providing increased air flow to remove friction dust, dirt, and other contaminants.
It is further an object of the present invention to provide such a novel rotational control apparatus having reduced mass.
It is further an object of the present invention to provide such a novel rotational control apparatus allowing elimination of expensive heat treatments.
It is further an object of the present invention to provide such a novel rotational control apparatus reducing the number of different castings.
These and further objects and advantages of the present invention will become clearer in light of the following detailed description of an illustrative embodiment of this invention described in connection with the drawings.